Shadow Mountain Reservoir Reservoir Report

Last Updated: January 12, 2026

Shadow Mountain Reservoir is a man-made lake in Grand County, Colorado, created in 1947 by the construction of a dam on the Colorado River.


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Summary

It has a capacity of 33,000 acre-feet and is used for hydroelectric power generation, irrigation, and recreational activities. The reservoir is fed by snowpack in the surrounding mountains and surface flows from the Colorado River and its tributaries. The Colorado-Big Thompson Project and the Windy Gap Project are the primary surface flow and snowpack providers to the reservoir. The water from Shadow Mountain Reservoir is used for irrigation of crops such as hay and potatoes in the surrounding farmland. Recreational activities such as fishing, boating, and camping are popular in the area.

Reservoir Details

Storage 24hr Change 0.0%
Percent of Normal 99%
Minimum 75.859 acre-ft
2008-06-12
Maximum 18,074.6 acre-ft
2006-07-10
Average 17,212 acre-ft
Nid_Height 63
Hydraulic_Height 37
Drainage_Area 187
Year_Completed 1945
Dam_Height 63
Structural_Height 63
River_Or_Stream COLORADO RIVER
Primary_Dam_Type Earth
Foundations Rock, Soil
Surface_Area 1852
Hazard_Potential High
Outlet_Gates Slide (sluice gate) - 1
Nid_Storage 18369
Dam_Length 3077
       
Seasonal Comparison
Storage Levels
Storage Levels
Pool Elevation Levels

Weather Forecast

Dam Data Reference

Condition Assessment

Satisfactory
No existing or potential dam safety deficiencies are recognized. Acceptable performance is expected under all loading conditions (static, hydrologic, seismic) in accordance with the minimum applicable state or federal regulatory criteria or tolerable risk guidelines.
Fair
No existing dam safety deficiencies are recognized for normal operating conditions. Rare or extreme hydrologic and/or seismic events may result in a dam safety deficiency. Risk may be in the range to take further action. Note: Rare or extreme event is defined by the regulatory agency based on their minimum
Poor A dam safety deficiency is recognized for normal operating conditions which may realistically occur. Remedial action is necessary. POOR may also be used when uncertainties exist as to critical analysis parameters which identify a potential dam safety deficiency. Investigations and studies are necessary.
Unsatisfactory
A dam safety deficiency is recognized that requires immediate or emergency remedial action for problem resolution.
Not Rated
The dam has not been inspected, is not under state or federal jurisdiction, or has been inspected but, for whatever reason, has not been rated.
Not Available
Dams for which the condition assessment is restricted to approved government users.

Hazard Potential Classification

High
Dams assigned the high hazard potential classification are those where failure or mis-operation will probably cause loss of human life.
Significant
Dams assigned the significant hazard potential classification are those dams where failure or mis-operation results in no probable loss of human life but can cause economic loss, environment damage, disruption of lifeline facilities, or impact other concerns. Significant hazard potential classification dams are often located in predominantly rural or agricultural areas but could be in areas with population and significant infrastructure.
Low
Dams assigned the low hazard potential classification are those where failure or mis-operation results in no probable loss of human life and low economic and/or environmental losses. Losses are principally limited to the owner's property.
Undetermined
Dams for which a downstream hazard potential has not been designated or is not provided.
Not Available
Dams for which the downstream hazard potential is restricted to approved government users.